Use stream of consciousness to answer the following. The Seine (/ seɪn / SAYN; French: La Seine, pronounced ( la sɛːn) ) is a 777-kilometre-long (483 mi) river and an important commercial waterway within the Paris Basin in the north of France. It rises at Source-Seine, 30 kilometres (19 mi) northwest of Dijon in northeastern France in the Langres plateau, flowing through Paris and into the English Channel at Le Havre (and Honfleur on the left bank). It is navigable by ocean-going vessels as far as Rouen, 120 kilometres (75 mi) from the sea. Over 60 percent of its length, as far as Burgundy, is negotiable by commercial riverboats, and nearly its whole length is available for recreational boating; excursion boats offer sightseeing tours of the Rive Droite and Rive Gauche within the city of Paris.

Where does the river seine start and end?
To answer this question, we should know that: It rises at Source-Seine, 30 kilometres (19 mi) northwest of Dijon in northeastern France in the Langres plateau, flowing through Paris and into the English Channel at Le Havre (and Honfleur on the left bank). Final answer: Source - Seine , 30 kilometres ( 19 mi ) northwest of Dijon in northeastern France in the Langres plateau , flowing through Paris and into the English Channel at Le Havre ( and Honfleur on the left bank ).